Rubber tubing for tires, &amp;c.



4 A. D. WARNER. RUBBER TUBING PoR ms, am. APPLIOATION FILED APB. 16. 1909.

Patented Jan. 4, 1910.

@Wit/@woe PATENT OFFICE.

ADNA D. WARNER, OF

MISHAWAKA, INDIANA.

RUBBER TUBING Fon, Tinus, ac.

To all whom it may concern:

Specification of Letters Patent.

Application filed April 16, 1909.

Patented Jan. 4, 1910.

Serial No. 490,224.

| of air cells, and, as these cells are opened by Be it known that I, ADNA D. WARNER, a l process ofwear, they cause rapid disintegracitizen of the United States, residing in Mishawaka, county of St. Joseph, and State of Indiana., have invented a certaln new and useful Improvement in Rubber Tubing for.

Tires, &c., of which the following is a specilication.

In a pending application of even date herewith berial No. 490,223 I have claimed a certain improved method or process for making rubber fabric.

The present invention relates to an 1mproved form of rubber tube especially useful for pneumatic tires for automobiles and the like; and the principal object of this invention is the production of such a tube which shall possess superior reliability and durability without material increase of exl pense.

The principal advantages found in tubing made according to my improved process are-first: superior durability as compared with former tubes of the same material and thieknessm-second: no increase in the cost of production-third: the tubes are made and applied by existing types of machines and therefore their' manufacture involves no change in existing plai'its-fourth :la thicker tube is producible without impairing the qualityrof the material. These advantages result from two principal features of improvement which I prefer to combine as hereinafter described. 'Ihe first of these features, which has reference to the mode of relating what l terni the line of rolling of the material in different layers, has for its object the prevention of breaking or checking in the fabric, and the distribution of 'the material so as io adapt it to successful rcsistance to thc strains to which pneumatic tires are subjected in practice. 'lhe second `featurc, having reference to cold rolling of the sheets wlnle building up the lubric, has y for its object the entire avoidance of air cells in the completed labric, and makes it possible especially in the preferred ar,- rangement described) to build up very thick tubes without danger olf imlierfections.

It is obviously desirable to make pneu matic tubes for heavy whicles of such a weight and tl'iickncss as will require the least possible inelastic covering to reinforce the rubber. But it is found in practice that the thicker a single sheet of rubber is rolled in calender-ing the greater is the proportion tionl of the material. On the other hand, where tubes are built up, as hitherto,l of separate calendered sheetsunite'd by cement, the utmost care cannot prevent formation of similar cells, due to lthe volatile ingredient of the rubber cement (generally benzene) permeating the mass of the rubber and producing a spongy texture by its expansion. I have discovered that separate calendered sheets of green or uncured rubber may be creased pressure as compared with the calenclering pressure, and that, where this process is resorted to, practicall all spongy tex ture is done away with. I ave further discovered that by use of this rocess the peculiar internal structure of the material originally caused by the calendering rolls is not materially disturbed. This discovery has rendered possible the arrangement of the various sheets or layers as hereinafter described without sacrificing any of the advantages pointed out.

Where rubber compounds'are formed into sheets by passing them between hot calendering rolls the internal structure is modified, and I have found that the following qualities are observable.

First: The tensile strength is greater in the direction in which the rolling has occurred.' This direction I have termed the line ofrrolling.

Second: The elasticity or resilience is greater at right angles to this direction.

Third: The tendency to split or check is greater when a sheet is bent on curves whose axis is parallel to the line of rolling than when bent at right angles to.tl1is direction.

I have also discovered that, where calendered sheets of rubber compound are united ternal structure is not interfered with by the excessive pressure necessary in'connection with this process. Furthermore, I have found by practical commercial use that, by uniting sheets with their lines of rolling making material angles the one with the other, the advantageous qualities belongin r to each direction of the lines may be unite as hereinafter more fully set forth.

Iilitherto in building up rubber tires or other rubber tubing it has been the practice to roll the sheets around a mandrel lengthwise of the sheet, because, where tubes of united perfectly by rolling cold under in by cold rolling as above described, this in-y any 'convenient length are desired, it would crosswise.

not be practical-to make rollers wide enough to produce a sheet which could be rolled Consequently the lines of rolling in rubber tubes thus formed, run-lengthwise of the tube, and the bending of the fabric to form` the tube thus causes a permanent strain across the grain, which tends vto split the sheet lengthwise. In pneumatic tires forl wheels the very great strains brought upony the rubber tube in process of use soon cause small, longitudinal openings to show themselves, which give rise to leakage and rapidly cause-the tire to become useless. The discoveries above pointed out in connection with the advantages of roper. arrangement, and mode of. uniting o rubber sheets are 4peculiarly useful in providing a remedy for these evils in pneumatic tubes'. I have found that, by making rubber tubing of a number of united su erposed thin sheets placed so that the rollling line of at least one sheet shall makea material angle with that of others, a greatly increased life yis, secured and the tendency to open up along. the line of rolling is greatly diminished. In order to produce this result consistently with the use of rollers of reasonable width, I prefer the specific construction indicated in the a'ccompanying drawings, wherein#- Figure lA shows the method ofvsuperposing the sheets and of cutting out thepiece to be rolled to form the tire or other tube, Fig. 2 is a perspective View of. a portion of a straight tube on a mandrel, and Fig. 3 is a perspective view of such a tube bent around in a circle to bring the ends together to be joined in forming a tire.

In Fig. l the edges of two ordinary rolled sheets of uncured rubber vare indicated in dotted lines and the direction of the line of rolling in each is shown by the arrows. It

-will be seen that, with uncured sheets so placed, the line of rolling of each makes a material anglewith the other, and this angle will be determined by the necessary length and width of the final composite piece to be used and'by the practicak` width of the rollers for forming the' original sheets. By cutting appropriate lengths from the vtwo original sheets and placing them substantial y as shown in Fig. 1, it will be possible to cut a composite piece 10 (shown in full lines) from those portions of the .two which are superposed, and the length of' such a piece will be much longer than the width of either original sheet. In the drawing the proportion is about as seven to four. The portions l0v havingbeen thus cut out7 the separate sheets are united in a suitable manner, but, in order to avoid distortion or change of molecular arrangement, as well as to prevent the formation of air cells within the fabric, I prefer to unite these sheets by appliation of my discovery above pointaccomplished,

ed out. That is to say, I prefer to run the sheets together cold, in uncured condition,

the use of weights or springs. The pressure used is four or. ive times as great as that employed where mere cementing is to be or where sheets are united hot. The sheet thus produced is a composite one having the lines of rolling of the component parts placed'at an angle `t-oeach other. It is bent over a mandrel l2, as shown in Fig. 2, and is then removed therefrom and bent around as shown in Fig. 3, when a tire is to be made. The edges and ends having been proper-ly joined in any well known manner, the whole is vulcanized,..and -the 'tire is complete.

I find that-by making'a rubber tube or tire in the manner above described the tendency to split through and leak is much diminished, thus greatly increasing j the durability of the article.

It is to be understood that this'invention is not limited to the use of two layers or of any other specific number. Also the particular relative widths of sheets; theparticular anglev between lines of rolling, and

theparticular shape of the composite sheet are not essentials of my invention.

In my claims the term rubber applies t0 any of the well known compounds to.

which that term is commercially applied,

capable of treatment as above described. The expression united integrally indicates union of adjacent sheets without the intervention of foreign material such as the benzene or other volatile constituents of rubber cement which causes spongmess and consequent weakening of the fabric.

What I claim ism vl. As .an article of manufacture, arubber tube composed of a rolled rubber `superposed and united at their surfaces with the line of rolling ofat least one of said sheets making a material angle with that of another, substantially as described. l

2. As an article of manufacture, a rubber tube composed of a plurality of sheets of rolled rubbersuperposed and united integrally at their surfaces with the lineof rolling of atleast one of said sheets making a material angle with that of another, substantially as described. i

3. As an article ofl manufacture, a rubber tube composed of a plurality of calendei'ed sheets of rubber superposed and united integrally with the line of rolling of one or more of said sheets set across the line of roll ingI of another, substantially as described.

L The process of making rubber tubing which consists in laying a plurality of sheets of uncured rolled vrubber across each other with the line of rolling of one or more of plurality of sheets of f 'substantially as described. '5. The process of making .rubber` tubing said sheets makinga material angle with the grain .of others, cutting out unduniting a suitably shaped piece from they overlap ping-. portionsof said sheets, bending" said piece into tube shape, and uniting th edges.

which consists in superposing a plurality of caleudered sheets'A of rubber with their lines of'rollin-g crossed, uniting the same in-4 tegrally without disturbing their molecular rrang'emerit, bending them into 'n tube and unitingtheedges, substantiallyas described.

6. The process of making rubber tubing which consists in suporposing u plurality of 1 culendercd sheets of rubber with their lines of rolling' crossalysubjecting them While cold to a rolling pressure greatly in excess of the calendering pressure, bending them Witnesses:

H. S. MGKAYE, M. A.BUTLER.

into tube lshltpe and vulcanizing und uniting 20 

